1. Field of the Invention
The present invention relates to a technology for generating a vehicle image for identifying a vehicle.
2. Description of the Related Art
In the field of traffic monitoring, image data on vehicles traveling on a road are collected by a monitoring camera installed on the road. The image data are stored in a database with their attributes (for example, shooting date and time, and shooting location), so that the image data can be retrieved from the database when necessary.
However, because the volume of image data is generally large, the volume of image data to be stored becomes extremely large as vehicles whose images are captured by the monitoring camera increase.
As a result, the data volume reaches its maximum in a short term, and, to address such a situation, the image data are needed to be saved in a medium suitable for long storage such as a magnetooptic disk (MO) or a linear tape-open (LTO). In addition, because transmission of the image data to the database causes a high volume of data traffic, the system requires large running costs.
To solve the problems, there is a need of a technology for generating a downsized vehicle image suitable for transmission or storage from an original image of a vehicle. For example, Japanese Patent Application Laid-Open No. 2004-101470 discloses a conventional technology for, when the license plate of a vehicle is read without fails, extracting an image of the vehicle excluding a background from the original image, and generating a downsized image data based on the extracted image of the vehicle.
However, with the conventional technology, a data volume possible to be reduced is limited. An original image is shot focusing on a vehicle to be used for identifying the vehicle. That is, data volume of the background in the original image is relatively small. Removal of only the background from the original image cannot effectively reduce the data volume of the original image.
Thus, it has been focus on how to generate a vehicle image that contains information required for identifying a vehicle by removing needless data as well as the background from an original image.